JP6828360B2 - A liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, and a method for manufacturing a liquid crystal alignment film and a liquid crystal element. - Google Patents

Description

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, and a method for manufacturing the liquid crystal alignment film and the liquid crystal element.

The liquid crystal element has a liquid crystal alignment film for orienting liquid crystal molecules. In recent years, with the expansion of usage applications and usage environments, the demand for display performance of liquid crystal panels has become even more stringent. Therefore, various studies have been conducted on liquid crystal alignment films for improving various characteristics of liquid crystal panels (see, for example, Patent Documents 1 and 2). Patent Document 1 contains at least one polymer having photoalignment ability and a polymer exhibiting liquid crystallinity, and the polymer having photoalignment ability is selected from the group consisting of polyamic acid, partially imidized polyamic acid and polyimide. It is disclosed that a liquid crystal alignment film is formed by using a photoaligning agent. Further, in Patent Document 2, a liquid crystal alignment film is formed by forming a coating film on a substrate using a photosensitive side chain polymer that exhibits liquid crystal properties, irradiating it with polarized ultraviolet rays, and then heating it. Is disclosed to form.

Japanese Patent No. 5407394 International Publication No. 2013/081066

With the increasing versatility of liquid crystal elements, it is expected that they will be used in harsh environments such as continuous driving for a long time and use in places with light stress, but the liquid crystal elements deteriorate due to light during use (for example). It is important that the voltage retention rate is unlikely to decrease and that it can withstand use in harsh environments. It is also important that the initial voltage retention rate is high in order to improve the display quality of the liquid crystal element. Considering the recent demand for higher performance of the liquid crystal element, the initial voltage retention rate is high and the light resistance is high. There is a demand for new technology for obtaining liquid crystal elements with excellent properties.

The present invention has been made in view of the above problems, and one object of the present invention is to provide a liquid crystal alignment agent capable of obtaining a liquid crystal element having excellent initial voltage retention and light resistance.

The present inventor has diligently studied to achieve the above-mentioned problems of the prior art, and found that the above-mentioned problems can be solved by setting the polymer component of the liquid crystal aligning agent to a specific composition, and completed the present invention. I came to do it. Specifically, the following means are provided.

<1> A liquid crystal in at least one molecule of a polymer containing a polyorganosiloxane (C) having a photo-oriented group and different from the polyorganosiloxane (C) and the polyorganosiloxane (C). A liquid crystal alignment agent containing a partial structure that expresses sex.
<2> A liquid crystal alignment film formed by using the liquid crystal alignment agent according to <1> above.
<3> A liquid crystal element provided with the liquid crystal alignment film according to <2> above.
<4> The step of applying the liquid crystal alignment agent of <1> on the substrate to form a coating film, and irradiating the surface of the substrate to which the liquid crystal alignment agent is applied with light to impart the liquid crystal alignment ability to the coating film. A process and a method for producing a liquid crystal alignment film including.
<5> A step of forming a liquid crystal alignment film on each surface of a pair of substrates by the method of <4> above, and a polymerizable monomer on the pair of substrates so that the respective liquid crystal alignment films face each other. A method for manufacturing a liquid crystal element, which comprises a step of constructing a liquid crystal cell by arranging it via a liquid crystal layer including the liquid crystal layer, and a step of irradiating the liquid crystal cell with light.
<6> A step of forming a liquid crystal alignment film using a liquid crystal alignment agent containing a polymerizable monomer on each surface of a pair of substrates by the method of <4> above, and a step of forming a liquid crystal alignment film on each surface of the pair of substrates, respectively. A method for manufacturing a liquid crystal element, which comprises a step of constructing a liquid crystal cell by arranging the alignment films via a liquid crystal layer so as to face each other, and a step of irradiating the liquid crystal cell with light.

According to the liquid crystal alignment agent of the present disclosure, it is possible to obtain a liquid crystal element having a high initial voltage retention rate and excellent light resistance. Further, since the liquid crystal alignment agent of the present disclosure can produce a liquid crystal alignment film by applying the photoalignment method, the occurrence of display defects and the decrease in yield due to the generation of dust and static electricity are compared with the conventional rubbing method. It is also excellent in that it can uniformly impart the liquid crystal alignment ability to the organic thin film formed on the substrate.

The liquid crystal alignment agent of the present disclosure contains a polyorganosiloxane (C) having a photoaligning group. Further, as at least one of the polyorganosiloxane (C) and a polymer different from the polyorganosiloxane (C), a polymer having a partial structure exhibiting liquid crystallinity is contained.

The partial structure exhibiting liquid crystallinity may be possessed by the polyorganosiloxane (C), may be possessed by a polymer different from the polyorganosiloxane (C), and may be possessed by both of these polymers. You may be. From the viewpoint of the initial voltage retention and light resistance of the liquid crystal element, it is preferable that the partial structure exhibiting the liquid crystal property has a polymer different from that of the polyorganosiloxane (C). That is, the liquid crystal alignment agent of the present disclosure preferably contains a polymer (A) that exhibits liquid crystallinity in a predetermined temperature range and a polyorganosiloxane (C) having a photooriented group. The polymer (A) and the polyorganosiloxane (C) will be described in detail below, and other components optionally added to the liquid crystal alignment agent of the present disclosure will be described.

（式（１）中、Ａｒ^１及びＡｒ^２は、それぞれ独立に、置換又は無置換のフェニレン基又はシクロヘキシレン基であり、Ｘ^１は単結合、−ＣＯ−、−ＣＯＯ−、−Ｃ＝Ｃ−、−Ｃ≡Ｃ−、−Ｎ＝Ｎ−又は−ＣＯＮＲ^１−（Ｒ^１は水素原子又は１価の有機基である。）である。ｎは１〜３の整数である。ｎが２又は３のとき、Ａｒ^２，Ｘ^１は各々独立に上記定義を有する。「＊」は結合手を示す。） <Polymer (A)>
The structure of the polymer (A) is not particularly limited as long as it exhibits liquid crystallinity in a predetermined temperature range, and examples of the partial structure exhibiting liquid crystallinity include polymers having a rigid moiety (mesogen structure). .. Examples of the mesogen structure of the polymer (A) include a structure represented by the following formula (1).

(In formula (1), Ar ¹ and Ar ² are independently substituted or unsubstituted phenylene group or cyclohexylene group, respectively, and X ¹ is a single bond, -CO-, -COO-, -C = C. -, -C≡C-, -N = N- or -CONR ^1- (R ¹ is a hydrogen atom or a monovalent organic group). N is an integer of 1-3. N is 2. Or, when it is 3, Ar ² and X ¹ have the above definitions independently. “*” Indicates a bond.)

（式中、「＊」は結合手を示す。） In the above formula (1), X ¹ is preferably a single bond or -COO-. Examples of the monovalent organic group of R ¹ include an alkyl group having 1 to 6 carbon atoms and a protecting group. Specific examples of the protecting group include, for example, a t-butoxycarbonyl group, a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethyloxycarbonyl group, an allyloxycarbonyl group and the like.
As the substituent of the ring portion of Ar ¹ and Ar ² , an alkyl group or a halogen atom having 1 to 5 carbon atoms is preferable, and a methyl group or a fluorine atom is more preferable.
Preferred specific examples of the partial structure represented by the above formula (1) include, for example, 4-biphenyl group, 4-bicyclohexyl group, p-terphenyl group, 4,4'-biphenylene group, 4,4'-. A bicyclohexylene group, a p-terphenylene group, a group represented by each of the following formulas (1-1) to (1-4), a group having a methyl group or a fluorine atom in the ring portion of these groups, etc. Can be mentioned.

(In the formula, "*" indicates a bond.)

The polymer (A) may have a mesogen structure in either the main chain or the side chain of the polymer, but the side having the mesogen structure in the side chain is highly effective in improving the light resistance of the liquid crystal device. It is preferably a chain type liquid crystal polymer. Here, in the present specification, the "main chain" of a polymer means a part of a "stem" composed of a chain of longest atoms in a polymer. It is permissible for this "trunk" portion to contain a ring structure. Therefore, "having a mesogen structure in the main chain of the polymer" means that the structure constitutes a part of the main chain. The "side chain" of a polymer is a portion branched from the "stem" of the polymer. The polymer (A) may have a mesogen structure only in the main chain of the polymer, may have it only in the side chain, or may have it in both the main chain and the side chain. May be good.

The type of the main skeleton of the polymer (A) is not particularly limited, but from the viewpoint of affinity with liquid crystal and mechanical strength, a polymer of a monomer having a polymerizable unsaturated bond (hereinafter, "polymer") is preferable. (PAc) ”), is at least one selected from the group consisting of polyamic acid, polyimide and polyamic acid ester, and the polymer (PAc) is capable of improving the voltage retention and light resistance of the liquid crystal element. More preferred.

-Polymer (PAc)
The monomer used for the polymerization of the polymer (PAc) is not particularly limited as long as it has a polymerizable unsaturated bond, and examples thereof include (meth) acrylic compounds, conjugated diene compounds, aromatic vinyl compounds, and maleimide compounds. Be done. The polymer (PAc) is preferably a polymer obtained by using a monomer containing a (meth) acrylic compound as a raw material, because the effect of improving the light resistance of the liquid crystal element is high. In the synthesis of the polymer (PAc), the ratio of the (meth) acrylic compound used is preferably 50 mol% or more, preferably 60 mol% or more, based on the total amount of the monomers used in the synthesis. More preferably, it is more preferably 70 mol or more. In addition, in this specification, "(meth) acrylic" means including acrylic and methacrylic.

The polymer (PAc) is a functional group (hereinafter referred to as "photoreactive group") that undergoes a cross-linking reaction, an isomerization reaction, a photodimerization reaction, or a Fries rearrangement reaction in response to light, together with a partial structure exhibiting liquidity. May have. Examples of the photoreactive group include a (meth) acrylic-containing group having a (meth) acrylic acid or a derivative thereof as a basic skeleton, a group having a vinyl group (alkenyl group, styrene group, etc.), an ethynyl group, and an epoxy group (oxylanyl). Group, oxetanyl group), phenylbenzoate-containing group containing phenylbenzoate or its derivative as a basic skeleton, azobenzene-containing group containing azobenzene or its derivative as a basic skeleton, katsura acid structure-containing group containing katsura acid or its derivative as a basic skeleton, Examples thereof include a chalcone-containing group containing calcon or a derivative thereof as a basic skeleton, a benzophenone-containing group containing benzophenone or a derivative thereof as a basic skeleton, and a coumarin-containing group containing coumarin or a derivative thereof as a basic skeleton.

（式（２−１）〜式（２−５）中、Ｒ^２は水素原子又はメチル基であり、Ｒ^３は、炭素数１〜１２のアルカンジイル基又は当該アルカンジイル基の少なくとも１個のメチレン基を−Ｏ−で置換してなる２価の基であり、Ｒ^４は、炭素数１〜２０のアルキル基、フルオロアルキル基、アルコキシ基若しくはフルオロアルキル基、又はフッ素原子である。） The polymer (PAc) can be obtained, for example, by polymerizing a monomer having a polymerizable unsaturated bond in the presence of a polymerization initiator. The monomer used preferably contains a compound having a polymerizable unsaturated bond and a partial structure exhibiting liquid crystallinity. Specific examples of the monomer having a polymerizable unsaturated bond and a partial structure exhibiting liquid crystallinity include compounds represented by the following formulas (2-1) to (2-5). As these monomers, one type may be used alone, or two or more types may be used in combination.

(In formulas (2-1) to (2-5), R ² is a hydrogen atom or a methyl group, and R ³ is an alkanediyl group having 1 to 12 carbon atoms or at least one of the alkanediyl groups. a methylene group is the divalent group formed by substituted with -O-, R ⁴ is an alkyl group having 1 to 20 carbon atoms, a fluoroalkyl group, an alkoxy group or fluoroalkyl group, or a fluorine atom.)

In the synthesis of the polymer (PAc), a compound having no partial structure exhibiting liquid crystallinity may be used in combination as the monomer having a polymerizable unsaturated bond. The proportion of the compound having no partial structure exhibiting liquid crystallinity is preferably 50 mol% or less, preferably 40 mol% or less, based on the total amount of the monomers used for the synthesis of the polymer (PAc). It is more preferable to do so.

Examples of the polymerization initiator used for the above polymerization include 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), and 2,2'-azobis (4-). Examples thereof include azo compounds such as methoxy-2,4-dimethylvaleronitrile). The proportion of the polymerization initiator used is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of all the monomers used in the reaction. The polymerization is preferably carried out in an organic solvent. Examples of the organic solvent used in the reaction include alcohols, ethers, ketones, amides, esters, hydrocarbon compounds and the like, and specific examples thereof include diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether acetate, tetrahydrofuran and the like. .. The reaction temperature is preferably 30 ° C. to 120 ° C., and the reaction time is preferably 1 to 36 hours. The amount (a) of the organic solvent used should be such that the total amount (b) of the monomers used in the reaction is 0.1 to 60% by mass with respect to the total amount (a + b) of the reaction solution. Is preferable.

The polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polymer (PAc) is preferably 250 to 500,000, more preferably 500 to 100,000. It is more preferably 1,000 to 50,000. The polymer (PAc) may be used alone or in combination of two or more.

（式（３）中、Ｒ^５は２価の有機基である。） -Polyamic acid The polyamic acid as the polymer (A) (hereinafter, also referred to as "polyamic acid (A)") is not particularly limited as long as it exhibits liquid crystallinity, but has a mesogen structure in the main chain of the polymer. Those having can be preferably used. Such a polyamic acid can be obtained, for example, by polymerization using at least one of a tetracarboxylic dianhydride having a mesogen structure in the main chain and a diamine compound having a mesogen structure in the main chain as raw materials. An example of a polyamic acid exhibiting liquidity is a polymer obtained by reacting a tetracarboxylic dianhydride having a terphenyl skeleton in the main chain with a diamine compound, and specifically, the following formula ( Examples thereof include a polymer having a partial structure represented by 3).

(In the formula (3), ^{R 5} is a divalent organic group.)

In the above formula (3), the divalent organic group for R ⁵ are the remaining group obtained by removing two primary amino groups from a diamine compound. In terms of expressing liquid crystallinity polyamic acid, R ⁵ is a carbon of a straight-chain alkanediyl group or said alkanediyl group having 4 to 20 carbon atoms - a divalent group containing a -O- between carbon bond It is preferable to have.

The tetracarboxylic dianhydride used for the synthesis of the polyamic acid (A) may be only the tetracarboxylic dianhydride having a mesogen structure, but the tetracarboxylic dianhydride having no mesogen structure may be used in combination. May be good. The tetracarboxylic dianhydride is not particularly limited, and a known tetracarboxylic dianhydride can be used. In the synthesis of a polyamic acid exhibiting liquid crystallinity, the ratio of the tetracarboxylic dianhydride having a mesogen structure to be used may be 50 mol% or more with respect to the total amount of the tetracarboxylic dianhydride used in the synthesis. It is preferably 70 mol% or more, and more preferably 70 mol% or more.

Examples of the diamine compound used for the synthesis of the polyamic acid (A) include an aliphatic diamine, an alicyclic diamine, an aromatic diamine, and a diaminoorganosiloxane. Among these, aliphatic diamines can be preferably used, and alkylenediamines of 1,4-diaminobutane, hexamethylenediamine, and octamethylenediamine are more preferable. In the synthesis of the polyamic acid (A), the ratio of the alkylenediamine used is preferably 50 mol% or more, more preferably 60 mol% or more, based on the total amount of the diamine compounds used in the synthesis.

The polyamic acid (A) can be obtained by reacting the tetracarboxylic dianhydride as described above with a diamine compound, if necessary, with a molecular weight modifier. The ratio of the tetracarboxylic dianhydride used in the polyamic acid synthesis reaction to the diamine compound is 0.2 for the acid anhydride group of the tetracarboxylic dianhydride to 1 equivalent of the amino group of the diamine compound. A ratio of up to 2 equivalents is preferable. Examples of the molecular weight adjusting agent include acid monoanhydrides such as maleic anhydride and phthalic anhydride, monoamine compounds such as aniline, cyclohexylamine and n-butylamine, and monoisocyanate compounds such as phenylisocyanate and naphthylisocyanate. The ratio of the molecular weight adjusting agent used is preferably 20 parts by mass or less with respect to 100 parts by mass in total of the tetracarboxylic dianhydride and the diamine compound.

The synthetic reaction of the polyamic acid (A) is preferably carried out in an organic solvent. The reaction temperature at this time is preferably −20 ° C. to 150 ° C., and the reaction time is preferably 0.1 to 24 hours.
Examples of the organic solvent used in the reaction include aprotonic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Particularly preferred organic solvents are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol. And one or more selected from the group consisting of halogenated phenol can be used as a solvent, or a mixture of one or more of these with another organic solvent (for example, butyl cellosolve, diethylene glycol diethyl ether, etc.) can be used. preferable. The amount of the organic solvent used (a) shall be such that the total amount (b) of the tetracarboxylic dianhydride and the diamine is 0.1 to 50% by mass with respect to the total amount (a + b) of the reaction solution. Is preferable.
As described above, a reaction solution obtained by dissolving the polyamic acid (A) is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal alignment agent, or the polyamic acid contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent.

-Polyamic acid ester The polyamic acid ester as the polymer (A) is, for example, a method of reacting the polyamic acid (A) obtained by the above synthesis reaction with an esterifying agent (for example, alcohols); a tetracarboxylic acid diester. It can be obtained by a method of reacting with a diamine compound; a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound, or the like. The obtained polyamic acid ester may have only an amic acid ester structure, or may be a partial esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester may be used as it is for the preparation of the liquid crystal alignment agent, or the polyamic acid ester contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent. Good.

-The polyimide as the polyimide polymer (A) can be obtained, for example, by dehydrating and ring-closing the polyamic acid (A) synthesized as described above to imidize it. The polyimide may be a completely imidized product in which all of the amic acid structure possessed by its precursor polyamic acid is dehydrated and ring-closed, and only a part of the amic acid structure is dehydrated and ring-closed to form an amic acid structure and an imide. It may be a partially imidized product in which a ring structure coexists. The polyimide used in the reaction preferably has an imidization ratio of 20 to 99%, more preferably 30 to 90%. This imidization ratio represents the ratio of the number of imide ring structures to the total of the number of amic acid structures and the number of imide ring structures of polyimide as a percentage.

The dehydration ring closure of a polyamic acid is carried out, for example, by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to this solution, and heating as necessary. As the dehydrating agent, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 0.01 to 20 mol with respect to 1 mol of the amic acid structure of the polyamic acid. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collagen, lutidine, and triethylamine can be used. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 mol with respect to 1 mol of the dehydrating agent used. Examples of the organic solvent used in the dehydration ring closure reaction include organic solvents exemplified as those used in the synthesis of polyamic acids. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C. The reaction time is preferably 1.0 to 120 hours. In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal alignment agent, or the polyimide may be isolated and then used for the preparation of the liquid crystal alignment agent.

The solution viscosities of the polyamic acid, the polyamic acid ester, and the polyimide as the polymer (A) are preferably those having a solution viscosity of 10 to 800 mPa · s when a solution having a concentration of 10% by mass is used. It is more preferable that the solution has a viscosity of 500 mPa · s. The solution viscosity (mPa · s) is E-type for a polymer solution having a concentration of 10% by mass prepared using a good solvent of these polymers (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). It is a value measured at 25 ° C. using a rotational viscometer.
The polystyrene-equivalent weight average molecular weight (Mw) of polyamic acid, polyamic acid ester and polyimide measured by GPC is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less.

The temperature range in which the polymer (A) exhibits liquid crystallinity (hereinafter, also referred to as “liquid crystal temperature range”) is not particularly limited, but from the viewpoint of sufficiently increasing the orientation-regulating force and orientation stability of the obtained liquid crystal alignment film. The liquid crystal temperature range is preferably in the range of 90 to 380 ° C, more preferably in the range of 100 to 350 ° C.

（式（ｃｎ−１）中、Ｒ^１１は、水素原子、ハロゲン原子、炭素数１〜３のアルキル基、炭素数１〜３のアルコキシ基又はシアノ基である。Ｒ^１２は、フェニレン基、ビフェニレン基、ターフェニレン基若しくはシクロヘキシレン基、又はこれらの基が有する水素原子の少なくとも一部が、ハロゲン原子、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシ基若しくはシアノ基で置換された基である。Ａ^１１は、単結合、酸素原子、硫黄原子、炭素数１〜３のアルカンジイル基、−ＣＨ＝ＣＨ−、−ＮＨ−、＊^１−ＣＯＯ−、＊^１−ＯＣＯ−、＊^１−ＮＨ−ＣＯ−、＊^１−ＣＯ−ＮＨ−、＊^１−ＣＨ_２−Ｏ−又は＊^１−Ｏ−ＣＨ_２−（「＊^１」はＲ^１２との結合手を示す。）である。Ｒ^１３は、ハロゲン原子、炭素数１〜３のアルキル基、炭素数１〜３のアルコキシ基又はシアノ基である。ａは０または１であり、ｂは０〜４の整数である。但し、ｂが２以上の場合、複数のＲ^１３は同じでも異なっていてもよい。「＊」は結合手であることを示す。）

（式（ｃｎ−２）中、Ｒ^１４は、炭素数１〜２０の１価の有機基である。Ｒ^１５は、ハロゲン原子、炭素数１〜３のアルキル基、炭素数１〜３のアルコキシ基又はシアノ基である。Ａ^１２は、酸素原子、＊^１−ＣＯＯ−、＊^１−ＯＣＯ−、＊^１−ＮＨ−ＣＯ−又は＊^１−ＣＯ−ＮＨ−（「＊^１」はＲ^１６との結合手を示す。）である。Ｒ^１６は、炭素数１〜６のアルカンジイル基である。ｃは０又は１であり、ｄは０〜４の整数である。但し、ｄが２以上の場合、複数のＲ^１５は同一であっても異なっていてもよい。「＊」は結合手であることを示す。） <Polyorganosiloxane (C)>
The photooriented group contained in the polyorganosiloxane (C) is a functional group that imparts anisotropy to the film by a photoisomerization reaction, a photodimerization reaction, a photodecomposition reaction, or the like by light irradiation. The polyorganosiloxane (C) may have a photo-oriented group in either the main chain or the side chain, but those having the photo-oriented group in the side chain can be preferably used. Specific examples of the photo-oriented group contained in the polyorganosiloxane (C) include the above-mentioned azobenzene-containing group, cinnamic acid structure-containing group, chalcone-containing group, benzophenone-containing group, coumarin-containing group and the like. Of these, a cinnamic acid structure-containing group is preferable because of its high photosensitivity and easy introduction into the side chain. The cinnamic acid structure-containing group contained in the polyorganosiloxane (C) is at least one selected from the group consisting of a group represented by the following formula (cn-1) and a group represented by the following formula (cn-2). Is particularly preferable.

(In the formula (cn-1), R ¹¹ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a cyano group. R ¹² is a phenylene group or biphenylene. A group, a terphenylene group or a cyclohexylene group, or at least a part of hydrogen atoms contained in these groups is substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms or a cyano group. It was a group ^{.A 11} is a single bond, an oxygen atom, a sulfur atom, an alkanediyl group having 1 to 3 carbon ^{atoms, -CH = CH -, - NH} -, * 1 -COO -, * 1 -OCO-, ^{* 1 -NH-CO -, *} 1 -CO-NH -, * 1 -CH 2 -O- or ^* 1 -O-CH ₂ - ( ^{"* 1"} indicates a bond to ^{R 12.)} in R ¹³ is a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a cyano group. A is 0 or 1, and b is an integer of 0 to 4. However, when b is 2 or more, a plurality of R ^13s may be the same or different. “*” Indicates that the combination is a bond.)

(In the formula (cn-2), R ¹⁴ is a monovalent organic group having 1 to 20 carbon atoms. R ¹⁵ is a halogen atom, an alkyl group having 1 to 3 carbon atoms, and an alkoxy having 1 to 3 carbon atoms. ^{.A 12} is a group or a cyano group, an oxygen ^{atom, * 1 -COO -, * 1} -OCO -, * 1 -NH-CO- or ^* 1 -CO-NH - ( ^{"* 1"} and ^{R 16} R ¹⁶ is an alcoholic group having 1 to 6 carbon atoms. C is 0 or 1, and d is an integer of 0 to 4. However, d is 2 or more. In the case of, a plurality of R ^15s may be the same or different. “*” Indicates that the combination is a bond.)

Examples of the monovalent organic group of R ¹⁴ include an alkyl group having 1 to 3 carbon atoms, -R ^21- X ^2- R ²² and -R ²² (R ²¹ is a substituted or unsubstituted phenylene group or cyclohexylene group. R ²² is a substituted or unsubstituted phenyl group or cyclohexyl group, and X ² is a single bond, an oxygen atom, a sulfur atom, an alkanediyl group having 1 to 3 carbon atoms, -CH = CH-, -NH-. , -COO-, -NH-CO- or -CH _2- O-) and the like. Examples of the substituent of R ²¹ and R ²² include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a cyano group.

The method for synthesizing the polyorganosiloxane (C) is not particularly limited. As an example, a method of hydrolyzing and condensing a hydrolyzable silane compound containing an epoxy group and, if necessary, another silane compound, and then reacting a carboxylic acid having a photo-oriented group can be mentioned.
Examples of the silane compound containing an epoxy group include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2-( 3,4-Epylcyclohexyl) ethyltrimethoxysilane and the like can be mentioned. The other silane compounds are not particularly limited as long as they are hydrolyzable compounds, but for example, tetramethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, p-styryltrimethoxysilane, vinyltriethoxysilane, and 3-mercapto. Examples thereof include propyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, and trimethoxysilylpropylsuccinic anhydride. One type of silane compound may be used alone, or two or more types may be used in combination.

The hydrolysis / condensation reaction is carried out by reacting one or more of the silane compounds with water, preferably in the presence of a suitable catalyst and organic solvent. In the reaction, the ratio of water used is preferably 1 to 30 mol with respect to 1 mol of the silane compound (total amount). Examples of the catalyst to be used include acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds and the like. The amount of the catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, etc., but is, for example, 0.01 to 3 times the molar amount of the total amount of the silane compound. Examples of the organic solvent to be used include hydrocarbons, ketones, esters, ethers, alcohols and the like, and it is preferable to use a water-insoluble or poorly water-soluble organic solvent. The proportion of the organic solvent used is preferably 10 to 10,000 parts by mass with respect to a total of 100 parts by mass of the silane compound used in the reaction. Further, the above reaction is preferably carried out by heating in an oil bath or the like. At that time, the heating temperature is preferably 130 ° C. or lower, and the heating time is preferably 0.5 to 12 hours. After completion of the reaction, the organic solvent layer separated from the reaction solution is dried with a desiccant, if necessary, and then the solvent is removed to obtain an epoxy group-containing polyorganosiloxane.

The reaction of the epoxy group-containing polyorganosiloxane with the carboxylic acid is preferably carried out in the presence of a catalyst and an organic solvent. The proportion of the carboxylic acid used is preferably 5 mol% or more, more preferably 10 to 80 mol%, based on the epoxy group contained in the epoxy group-containing polyorganosiloxane. As the catalyst, for example, a compound known as a so-called curing accelerator that promotes the reaction of an organic base or an epoxy compound can be used. The ratio of the catalyst used is preferably 100 parts by weight or less with respect to 100 parts by weight of the epoxy group-containing polysiloxane. Preferred specific examples of the organic solvent used include 2-butanone, 2-hexanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, butyl acetate and the like. The organic solvent is preferably used in a proportion such that the solid content concentration is 5 to 50% by weight. The reaction temperature in the above reaction is preferably 0 to 200 ° C., and the reaction time is preferably 0.1 to 50 hours. After completion of the reaction, the organic solvent layer separated from the reaction solution is dried with a desiccant if necessary, and then the solvent is removed to obtain a polyorganosiloxane (C) having a photo-oriented group. Can be done.
The method for synthesizing the polyorganosiloxane (C) is not limited to the above-mentioned hydrolysis / condensation reaction, and may be carried out, for example, by reacting a hydrolyzable silane compound in the presence of oxalic acid and alcohol. Further, in order to obtain a polyorganosiloxane having a photo-oriented group in the side chain, a polymerization method using a hydrolyzable silane compound having a photo-oriented group as a raw material may be adopted.

For the polyorganosiloxane (C), the polystyrene-equivalent weight average molecular weight measured by GPC is preferably 500 to 1,000,000, more preferably 1,000 to 100,000, and further 1, It is preferably 000 to 50,000. As the polyorganosiloxane (C), one type may be used alone, or two or more types may be used in combination.

The liquid crystal alignment agent of the present disclosure preferably contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester and polyimide in the polymer component. The polymer may be a polymer (A) that exhibits liquid crystallinity in a predetermined temperature range, or may be a polymer that does not exhibit liquid crystallinity. A preferred embodiment of the liquid crystal alignment agent of the present disclosure is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide as a polymer component, and a non-liquid crystal polymer (hereinafter, "polymer (B)". ) ”Is also included. By containing such a polymer (B), it is preferable in that the effect of improving the initial voltage retention rate and the light resistance of the liquid crystal element can be enhanced.

The polyamic acid as the polymer (B) (hereinafter, also referred to as “polyamic acid (B)”) can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine compound. Specific examples of the tetracarboxylic acid dianhydride used for the synthesis of polyamic acid include aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic hydride and ethylenediamine tetraacetate dianhydride. Anhydrides and the like; as alicyclic tetracarboxylic acid dianhydrides, for example 1,2,3,4-cyclobutanetetracarboxylic hydride, 1,3-dimethyl-1,2-2,3,4-cyclobutanetetracarboxylic Acid dianhydride, 2,3,5-tricarboxycyclopentylacetic hydride, 5- (2,5-dioxo tetrahydrofuran-3-yl) -3a, 4,5,9b-tetrahydronaphtho [1,2- c] Fran-1,3-dione, 5- (2,5-dioxo tetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] Fran-1 , 3-Dione, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 2,4,6,8-tetracarboxybicyclo [ 3.3.0] Octane-2: 4, 6: 8-anhydride, cyclohexanetetracarboxylic acid dianhydride, etc .; as aromatic tetracarboxylic acid dianhydride, for example, pyromellitic acid dianhydride, 4, 4'-(Hexafluoroisopropylidene) diphthalic anhydride, p-phenylenebis (trimeritic acid monoester anhydride), ethylene glycol bis (anhydrotrimeritate), 1,3-propylene glycol bis (anhydrotri) Meritate) and the like; can be mentioned, and the tetracarboxylic dianhydride described in JP-A-2010-97188 can be used. The tetracarboxylic dianhydride may be used alone or in combination of two or more.

（式（Ｅ−１）中、Ｘ^I及びＸ^IIは、それぞれ独立に、単結合、−Ｏ−、−ＣＯＯ−又は−ＯＣＯ−であり、Ｒ^Ｉは炭素数１〜３のアルカンジイル基であり、Ｒ^ＩＩは単結合又は炭素数１〜３のアルカンジイル基であり、ａは０又は１であり、ｂは０〜２の整数であり、ｃは１〜２０の整数であり、ｄは０又は１である。但し、ａ及びｂが同時に０になることはない。） Specific examples of the diamine compound used for the synthesis of the polyamic acid (B) include as an aliphatic diamine, for example, metaxylylene diamine, 1,3-propanediamine, hexamethylenediamine, and the like; as an alicyclic diamine, for example, 1. , 4-Diaminocyclohexane, 4,4'-methylenebis (cyclohexylamine), etc .; as aromatic diamines, for example, dodecanoxidiaminobenzene, octadecanoxidiaminobenzene, cholestanoloxydiaminobenzene, cholesteryloxydiaminobenzene, diamino Cholestanyl benzoate, cholesteryl diaminobenzoate, lanostanyl diaminobenzoate, 3,6-bis (4-aminobenzoyloxy) cholesterol, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-butylcyclohexane , 2,5-Diamino-N, N-diallylaniline, side chain diamines such as compounds represented by the following formula (E-1):

(In the formula (E-1), X ^I and X ^II is independently a single bond, -O -, - COO- or a -OCO-, ^{R I} is alkanediyl group having 1 to 3 carbon atoms Yes, R ^II is a single bond or an alkanediyl group with 1-3 carbon atoms, a is 0 or 1, b is an integer 0-2, c is an integer 1-20, d is It is 0 or 1. However, a and b cannot be 0 at the same time.)

p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 1,5-bis (4-aminophenoxy) pentane, bis [2- ( 4-Aminophenyl) ethyl] hexanedioic acid, N, N-bis (4-aminophenyl) methylamine, 2,6-diaminopyridine, 1,4-bis- (4-aminophenyl) -piperazin, N, N '-Bis (4-aminophenyl) -benzidine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, diaminobenzoic acid , 4,4'-Diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4'-(phenylenedi) Isopropyridene) bisaniline, 4- (4-aminophenoxycarbonyl) -1- (4-aminophenyl) piperidine, 4,4'-[4,4'-propane-1,3-diylbis (piperidin-1,4-) Diyl)] Main chain diamines such as dianiline and cinnamic acid structure-containing diamines; diaminoorganosiloxanes include, for example, 1,3-bis (3-aminopropyl) -tetramethyldisiloxane; , JP-A-2010-97188 can be used. The diamine compound may be used alone or in combination of two or more.

The polyamic acid (B) can be obtained by reacting the tetracarboxylic dianhydride as described above with a diamine compound, if necessary, with a molecular weight modifier. The description of the polyamic acid (A) can be applied to the molecular weight modifier, the polymerization solvent, the reaction conditions, etc. used in the reaction.
The polyamic acid ester and polyimide as the polymer (B) can be obtained in the same manner as in the case of the polymer (A) except that the polyamic acid (B) is used instead of the polyamic acid (A), for example. The description of the polymer (A) is applied to the solution viscosity, the weight average molecular weight and the number average molecular weight of the polymer (B).

The polymer component in the liquid crystal alignment agent of the present disclosure is preferably in any of the following embodiments [1] to [4].
[1] An embodiment in which a polymer (A) and a polyorganosiloxane (C) are contained as polymer components, and the polymer (A) is a polymer (PAc).
[2] An embodiment in which the polymer (A) and the polyorganosiloxane (C) are contained as polymer components, and the polymer (A) is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide.
[3] An embodiment in which a polymer (A), a polymer (B), and a polyorganosiloxane (C) are contained as polymer components, and the polymer (A) is a polymer (PAc).
[4] The polymer component includes the polymer (A), the polymer (B), and the polyorganosiloxane (C), and the polymer (A) is selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. At least one aspect.
Of these, [1] and [3] are more preferable, and [3] is particularly preferable, from the viewpoint of the initial voltage retention rate and the light resistance of the liquid crystal element. The polymer (A) and the polymer (B) may be photosensitive with exposure to light-induced anisotropy of the polyorganosiloxane (C). It may be non-photosensitive. It is preferably non-photosensitive in terms of initial voltage retention and light resistance of the liquid crystal element.

In the liquid crystal alignment agent of the present disclosure, the content ratio of the polymer (A) and the polyorganosiloxane (C) is the polymer (A) from the viewpoint of sufficiently obtaining the effect of improving the initial voltage retention rate and the light resistance of the liquid crystal element. The amount is preferably 1 to 80 parts by mass, more preferably 3 to 70 parts by mass, and 5 to 60 parts by mass with respect to 100 parts by mass of the total polymer components contained in the liquid crystal alignment agent. Is more preferable. The polyorganosiloxane (C) is preferably 1 to 99 parts by mass, more preferably 5 to 95 parts by mass, based on 100 parts by mass of the total polymer components contained in the liquid crystal alignment agent. It is more preferably 10 to 90 parts by mass. The ratio of the polymer (A) to the polyorganosiloxane (C) is preferably a mass ratio of polymer (A): polyorganosiloxane (C) = 5:95 to 70:30. : 90 to 60:40 is more preferable.
When the polymer (B) is blended with the liquid crystal alignment agent of the present disclosure, the content ratio of the polymer (B) is 1 to 95% by mass with respect to a total of 100 parts by mass of the polymer components contained in the liquid crystal alignment agent. The amount is preferably 20 to 90 parts by mass, more preferably 40 to 80 parts by mass.

The liquid crystal alignment agent of the present disclosure may contain other components other than the polymer (A) and the polyorganosiloxane (C) together with the polymer (A) and the polyorganosiloxane (C). Other components include, in addition to the polymer (B), for example, other polymers other than the polymer (A), the polymer (B) and the polyorganosiloxane (C), and at least one epoxy group in the molecule. Examples thereof include compounds having, functional silane compounds, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers and the like. The blending ratio of the other components can be appropriately selected according to each compound as long as the effects of the present disclosure are not impaired.

(solvent)
The liquid crystal alignment agent of the present disclosure is prepared as a liquid composition in which a polymer component and other components used as needed are preferably dispersed or dissolved in a suitable solvent. Examples of the organic solvent used include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide. , N, N-Dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, Ethyl glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl Examples thereof include ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate and propylene carbonate. These can be used alone or in admixture of two or more.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., but is preferable. It is in the range of 1 to 10% by mass. That is, the liquid crystal alignment agent is applied to the surface of the substrate as described later, and is preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. At this time, if the solid content concentration is less than 1% by mass, the film thickness of the coating film becomes too small and it becomes difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by mass, the film thickness of the coating film becomes excessive and it is difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases and the coatability deteriorates. There is a tendency.

<Liquid crystal element>
The liquid crystal element of the present disclosure includes a liquid crystal alignment film formed by using the liquid crystal alignment agent described above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and for example, TN type, STN type, vertically oriented type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB (Optically Compensated Bend). ) Can be applied to various modes such as type. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, the substrate used differs depending on the desired operation mode. Steps 2 and 3 are common to each operation mode.

[Step 1: Formation of coating film]
First, a liquid crystal alignment agent is applied on the substrate, and then, if necessary, the coated surface is heated to form a coating film on the substrate. As the substrate, for example, glass such as float glass and soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and poly (aliphatic olefin) can be used. As the transparent conductive film provided on one surface of a substrate, NESA film (US PPG registered trademark) made of tin oxide (SnO _2), indium oxide - such as an ITO film made of tin oxide _{(In 2} O 3 -SnO ₂₎ the Can be used. When manufacturing a TN type, STN type or vertically oriented type liquid crystal element, two substrates provided with a patterned transparent conductive film are used. In the case of manufacturing a transverse electric field type liquid crystal element such as an IPS type or an FFS type, a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb-tooth shape and a substrate having no electrode provided are opposed to each other. Use with a substrate. As the metal film, a film made of a metal such as chromium can be used. The coating on the substrate is preferably performed on the electrode forming surface by an offset printing method, a spin coating method, a roll coater method or an inkjet printing method.

After applying the liquid crystal alignment agent, preheating is preferably performed for the purpose of preventing the applied liquid crystal alignment agent from dripping. The pre-baking temperature is preferably 30 to 200 ° C., and the pre-baking time is preferably 0.25 to 10 minutes. After that, a firing (post-baking) step is carried out for the purpose of completely removing the solvent and, if necessary, thermally imidizing the amic acid structure present in the polymer. The firing temperature (post-baking temperature) at this time is preferably 80 to 300 ° C., and the post-baking time is preferably 5 to 200 minutes. The film thickness of the film thus formed is preferably 0.001 to 1 μm.

[Step 2: Orientation process]
When manufacturing a TN type, STN type, IPS type or FFS type liquid crystal element, a treatment (alignment treatment) for imparting a liquid crystal alignment ability to the coating film formed in the above step 1 is performed. As a result, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. The alignment treatment includes a rubbing treatment that imparts liquid crystal alignment ability to the coating film by rubbing the coating film in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, and cotton, and a substrate coated with a liquid crystal alignment agent. Examples thereof include a photo-alignment treatment in which a surface is irradiated with light to impart a liquid crystal alignment ability to a coating film. The liquid crystal alignment agent of the present disclosure is capable of imparting sufficient liquid crystal orientation regulating force by irradiating the coating film with light, and can suppress the occurrence of display defects and the decrease in yield due to the generation of dust and static electricity, and the substrate. The photo-alignment treatment can be preferably applied in that the liquid crystal alignment ability can be uniformly imparted to the organic thin film formed above. In the case of producing a vertically oriented liquid crystal element, the coating film formed in the above step 1 can be used as it is as a liquid crystal alignment film, but the coating film may be subjected to an orientation treatment.

In the photo-alignment treatment, as the light to irradiate the coating film, for example, ultraviolet rays including light having a wavelength of 150 to 800 nm and visible light can be used. Preferably, it is ultraviolet light containing light having a wavelength of 200 to 400 nm. When the irradiation light is linearly polarized light or partially polarized light, the irradiation may be performed from a direction perpendicular to the substrate surface, may be performed from an oblique direction, or may be performed in combination thereof. When irradiating unpolarized radiation, the direction of irradiation is diagonal.
As the light source to be used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. Ultraviolet rays in a preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter or a diffraction grating. The irradiation amount of radiation is preferably 200 to 50,000 J / m ² , and more preferably 400 to 20,000 J / m ² . The light irradiation for imparting the orientation ability may be applied to the coating film after the post-baking step, the coating film after the pre-baking step and before the post-baking step, or the pre-baking step and It may be applied to the coating film during heating in at least one of the post-baking steps.

[Step 3: Construction of liquid crystal cell]
A liquid crystal cell is manufactured by preparing two substrates on which the liquid crystal alignment film is formed as described above and arranging the liquid crystal between the two substrates arranged opposite to each other. Specifically, a method in which the peripheral portions of a pair of substrates are bonded together with a sealant, the liquid crystal is injected and filled into the surface of the substrate and the cell gap partitioned by the sealant, and then the injection holes are sealed; A sealant is applied to the peripheral part on the liquid crystal alignment film side, liquid crystal is dropped on a predetermined number of places on the liquid crystal alignment film surface, and then the other substrate is bonded so that the liquid crystal alignment film faces each other and the liquid crystal is attached to the substrate. A method of spreading the liquid crystal over the entire surface of the liquid crystal and then curing the sealant (ODF method).
Examples of the sealing agent include an epoxy resin containing an aluminum oxide sphere as a curing agent and a spacer. Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, nematic liquid crystal is preferable, and for example, shift-based liquid crystal, azoxy-based liquid crystal, biphenyl-based liquid crystal, phenylcyclohexane-based liquid crystal, ester-based liquid crystal, terphenyl-based liquid crystal, and biphenylcyclohexane. Examples thereof include liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, and Cuban liquid crystals. Further, a cholesteric liquid crystal, a chiral agent, a ferroelectric liquid crystal or the like may be added to these liquid crystals for use.

In step 3, a liquid crystal cell containing a polymerizable monomer is constructed in the liquid crystal layer, and the constructed liquid crystal cell is irradiated with light to polymerize the polymerizable monomer to impart initial orientation of the liquid crystal. You may. By performing this process, it is preferable to obtain a liquid crystal element having a high initial voltage retention rate and excellent light resistance when applied to a transverse electric field type such as an IPS type or an FFS type.

As the polymerizable monomer, a compound having two or more (meth) acryloyl groups can be preferably used because it is highly polymerizable by light. Specific examples thereof include di (meth) acrylate having a biphenyl structure, di (meth) acrylate having a phenyl-cyclohexyl structure, di (meth) acrylate having a 2,2-diphenylpropane structure, and di (meth) acrylate having a diphenylmethane structure. Meta) acrylate, di-thio (meth) acrylate having a diphenylthioether structure, di (meth) acrylate having a naphthalene structure, di (meth) acrylate having an anthracene structure, di (meth) acrylate having a phenanthrene structure, by light irradiation Examples thereof include di (meth) acrylate having a structure for generating a radical. The mixing ratio of the polymerizable monomer is preferably 0.1 to 1.0% by mass with respect to the total amount of the liquid crystal composition used for forming the liquid crystal layer. As the polymerizable monomer, one type may be used alone, or two or more types may be used in combination.

The light irradiation to the liquid crystal cell may be performed without applying a voltage between the pair of electrodes, may be performed with a predetermined voltage (for example, 0V) that does not drive the liquid crystal molecules in the liquid crystal layer, or may be performed. It may be performed in a state where a predetermined voltage for driving the liquid crystal molecules is applied. When the liquid crystal aligning agent of the present disclosure is applied to a liquid crystal element including a transverse electric field type liquid crystal cell, it is preferable to irradiate the liquid crystal cell with light without applying a voltage between the pair of electrodes. As the light to be irradiated, for example, ultraviolet rays containing light having a wavelength of 150 to 800 nm and visible light can be used, but ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferable. When the radiation to be used is linearly polarized light or partially polarized light, the light irradiation direction may be performed from a direction perpendicular to the substrate surface, may be performed from an oblique direction, or may be performed in combination of these. When irradiating unpolarized radiation, the irradiation direction is diagonal.

As the light source of the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. The ultraviolet rays in the above-mentioned preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter diffraction grating or the like. The irradiation dose of light, preferably 1,000~200,000J / ^{m 2,} more preferably from 1,000~100,000J / ^{m 2.}

Instead of mixing the polymerizable monomer in the liquid crystal layer, the polymerizable monomer may be mixed in the liquid crystal alignment film, and the liquid crystal cell may be irradiated with light to impart initial orientation to the liquid crystal. In this case, in step 1, a coating film is formed on the substrate using a liquid crystal alignment agent containing a polymerizable monomer. As the polymerizable monomer contained in the liquid crystal alignment agent, the description of the polymerizable monomer contained in the liquid crystal layer is applied. The content ratio of the polymerizable monomer is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass, based on 100 parts by mass of the total of the polymer components contained in the liquid crystal aligning agent.

Subsequently, if necessary, a polarizing plate is attached to the outer surface of the liquid crystal cell to obtain a liquid crystal element. Examples of the polarizing plate include a polarizing plate in which a polarizing film called "H film" in which polyvinyl alcohol is stretch-oriented and iodine is absorbed is sandwiched between a cellulose acetate protective film, or a polarizing plate made of the H film itself.

The liquid crystal elements of the present disclosure can be effectively applied to various applications, for example, clocks, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors. , LCD TVs, information displays and other display devices, dimming films and the like. Further, the liquid crystal element formed by using the liquid crystal alignment agent of the present disclosure can also be applied to a retardation film.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

In the following examples, the weight average molecular weight Mw and the epoxy equivalent of the polymer were measured by the following methods.
[Weight average molecular weight of polymer Mw]: From the results measured by gel permeation chromatography under the following conditions using the following apparatus, monodisperse polystyrene was used as a standard substance and determined as a polystyrene-equivalent value.
Measuring device: Tosoh Corporation, model "8120-GPC"
Column: "TSKgelGRCXLII" manufactured by Tosoh Corporation
Solvent: tetrahydrofuran Sample concentration: 5% by weight
Sample injection volume: 100 μL
Column temperature: 40 ° C
Column pressure: 68 kgf / cm ²
[Epoxy equivalent]: Measured according to the "hydrochloric acid-methyl ethyl ketone method" of JIS C2105.

［合成例２］
上記式（ｍ−１）で表される化合物に替えて下記式（ｍ−２）で表される化合物を使用した以外は上記合成例１と同様の操作により重合体（Ａ−２）を得た。この重合体（Ａ−２）は１０８〜３１３℃の温度範囲で液晶性を示した。

［合成例３］
１，８−ジアミノオクタン０．７００９ｇ（４．８５８ｍｍｏｌ）をＮ−メチル−２−ピロリドン（ＮＭＰ）２２．５ｇに溶解し、下記式（ｍ−３）で表される化合物１．７９９１ｇ（４．８５８ｍｍｏｌ）を室温で加えた。６０℃で２時間撹拌後、室温に冷却し、重合体（Ａ−３）を含有する溶液を得た。得られた重合体溶液を大過剰のメタノール中に注ぎ、反応生成物を沈殿させた。この沈殿物をメタノールで洗浄し、減圧下４０℃で１５時間乾燥させることにより重合体（Ａ−３）を得た。この重合体（Ａ−３）は１００〜２３５℃の温度範囲で液晶性を示した。

<Synthesis of polymer (A)>
[Synthesis Example 1]
The compound represented by the following formula (m-1) was dissolved in tetrahydrofuran, and azobisisobutyronitrile was added as a polymerization initiator to carry out the polymerization to obtain a solution containing the polymer (A-1). For the obtained polymer solution, the solvent in the system was replaced with N-methyl-2-pyrrolidone (NMP) to obtain a polymer (A-1). This polymer (A-1) exhibited liquid crystallinity in the temperature range of 116 to 315 ° C.

[Synthesis Example 2]
The polymer (A-2) was obtained by the same operation as in Synthesis Example 1 except that the compound represented by the following formula (m-2) was used instead of the compound represented by the above formula (m-1). It was. This polymer (A-2) exhibited liquid crystallinity in the temperature range of 108 to 313 ° C.

[Synthesis Example 3]
0.7009 g (4.858 mmol) of 1,8-diaminooctane was dissolved in 22.5 g of N-methyl-2-pyrrolidone (NMP), and 1.7991 g (4.) of the compound represented by the following formula (m-3) was dissolved. 858 mmol) was added at room temperature. After stirring at 60 ° C. for 2 hours, the mixture was cooled to room temperature to obtain a solution containing the polymer (A-3). The resulting polymer solution was poured into a large excess of methanol to precipitate the reaction product. The precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain a polymer (A-3). This polymer (A-3) exhibited liquid crystallinity in the temperature range of 100 to 235 ° C.

<Synthesis of polyorganosiloxane (C)>
[Synthesis Example 4]
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser was charged with 100.0 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 500 g of methylisobutylketone and 10.0 g of triethylamine at room temperature. Mixed in. Then, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and then the mixture was reacted at 80 ° C. for 6 hours while mixing under reflux. After completion of the reaction, the organic layer was taken out, washed with a 0.2 mass% ammonium nitrate aqueous solution until the water after washing became neutral, and then the solvent and water were distilled off under reduced pressure to obtain an epoxy group-containing polymer. A polymer (EPS-1) was obtained as an organosiloxane as a viscous transparent liquid. When ¹ H-NMR analysis was performed on this polymer (EPS-1), a peak based on the oxylanyl group was obtained near chemical shift (δ) = 3.2 ppm according to the theoretical intensity, and the epoxy group was found during the reaction. It was confirmed that no side reaction had occurred. The weight average molecular weight of this polymer (EPS-1) was 2,200, and the epoxy equivalent was 186 g / mol.
Next, in a 100 mL three-necked flask, 9.3 g of the polymer (EPS-1) obtained above, 26 g of methyl isobutyl ketone, 3.0 g of the compound represented by the following formula (m-4), and the trade name "UCAT 18X". (A quaternary amine salt manufactured by San-Apro Co., Ltd.) was charged, and the reaction was carried out at 80 ° C. for 12 hours with stirring. After completion of the reaction, the reaction mixture was poured into methanol to collect the resulting precipitate, which was dissolved in ethyl acetate to prepare a solution, which was washed with water three times and then the solvent was distilled off to obtain a polyorgano. 6.3 g of the polymer (C-1) as a siloxane (C) was obtained as a white powder. The weight average molecular weight Mw of this polymer (C-1) was 3,500.

<Other ingredients>
[Synthesis Example 5]
100 parts of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 100 parts of 4,4'-diaminodiphenyl ether as diamine were dissolved in NMP and reacted at 40 ° C. for 3 hours. A solution containing 10% by mass of the polymer (B-1) as a polyamic acid was obtained.
[Synthesis Example 6]
100 parts of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 100 parts of 4-aminophenyl-4'-aminoazobenzene as diamine were dissolved in NMP at 40 ° C. By reacting for 3 hours, a solution containing 10% by mass of the polymer (B-2) as a polyamic acid was obtained.
[Synthesis Example 7]
A polymer (D-1) was obtained by the same procedure as in Synthesis Example 1 except that octyl methacrylate was used in place of the compound represented by the above formula (m-1).

[Example 1]
(1) Preparation of liquid crystal aligning agent 20 parts by mass of the polymer (A-1) obtained in Synthesis Example 1 as the polymer (A), and the polymer (B-) obtained in Synthesis Example 5 as the polymer (B). The amount of the solution containing 1) corresponding to 60 parts by mass in terms of the polymer (B-1) and the polymer (C-1) 20 obtained as polyorganosiloxane (C) in Synthesis Example 4 above. Parts by mass were mixed, and N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added thereto, the solvent composition was NMP: BC = 50: 50 (mass ratio), and the solid content concentration was 4.0% by mass. Was used as the solution. A liquid crystal alignment agent was prepared by filtering this solution through a filter having a pore size of 1 μm.
(2) Production of Liquid Crystal Display Element Two glass substrates with transparent electrodes made of ITO film were prepared, and the liquid crystal alignment agent prepared in (1) above was applied onto each transparent electrode surface using a spin coater. Then, after prebaking on a hot plate at 80 ° C. for 1 minute, the inside of the oven was heated (post-baked) at 230 ° C. for 30 minutes in a nitrogen-substituted oven to form a coating film having a film thickness of 0.1 μm. Next, the surface of each coating film is irradiated with polarized ultraviolet rays of 500 mJ / cm ² containing a bright line of 313 nm from the normal direction of the substrate using an Hg-Xe lamp and a Gran Tailor prism, and a pair of substrates having a liquid crystal alignment film (2). Sheet) Made. It should be noted that this irradiation amount is a value measured using a photometer measured based on the wavelength of 313 nm. Subsequently, for one of the pair of substrates, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied to the outer edge of the surface having the liquid crystal alignment film, and then the pair of substrates have the liquid crystal alignment film surface. The adhesive was cured by overlapping and crimping so as to face each other. Next, a nematic liquid crystal (MLC-6221, manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photocurable adhesive to manufacture a liquid crystal cell. A liquid crystal display element was manufactured by laminating polarizing plates on both outer sides of the liquid crystal cell so that the changing directions of the two polarizing plates were orthogonal to each other.

(3) Evaluation of initial voltage retention rate After applying a voltage of 5 V to the liquid crystal display element immediately after being manufactured in (2) above at a temperature of 60 ° C. for an application time of 60 microseconds and a span of 167 milliseconds. The voltage holding rate (initial voltage holding rate VH ₁ ) 167 milliseconds after the application was released was measured. The measuring device used was the product name "VHR-1" manufactured by Toyo Technica Co., Ltd. As a result, in Example 1, VH ₁ = 99.6%.
(4) Evaluation of Light Resistance The liquid crystal display element after measuring the initial voltage retention rate VH ₁ was irradiated with light for 500 hours using a weather meter using a carbon arc as a light source. The voltage retention rate of the liquid crystal display element after light irradiation was measured in the same manner as in (3) above. This value was defined as VH _2, and the amount of decrease in the voltage holding ratio obtained by subtracting VH ₂ from VH ₁ was defined as ΔVHR, and the light resistance was evaluated by ΔVHR. As a result, in Example 1, ΔVHR = 0.6%, and the light resistance was good.
(5) Evaluation of liquid crystal orientation The liquid crystal alignment agent prepared in (1) above is applied and photoaligned to the surfaces of a pair of glass substrates not provided with electrodes in the same manner as in (2) above. A liquid crystal alignment film was formed, and a liquid crystal cell was manufactured in the same manner as in (2) above using a pair of substrates having the liquid crystal alignment film. When the obtained liquid crystal cell was observed under orthogonal Nicol, a uniform liquid crystal orientation without misalignment was observed.
Further, when the presence or absence of an orientation defect (abnormal domain) in the change of brightness when a voltage of 5 V was turned ON / OFF (applied / released) to the liquid crystal display element obtained in (2) above was visually observed, this liquid crystal was found. The display element had no orientation defects over the entire surface, and a uniform change in the orientation of the liquid crystal due to voltage application was observed.

[Examples 2 to 8 and Comparative Examples 1 to 11]
The liquid crystal alignment agent was prepared at the same solvent ratio and solid content concentration as in Example 1 above, except that the type and amount (parts by mass) of the polymer component used for preparing the liquid crystal alignment agent were changed as shown in Table 1 below. did. In addition, the liquid crystal alignment agent used was changed as shown in Table 1 below, and the exposure wavelength during the photoalignment treatment was changed from 313 nm to 365 nm for Comparative Examples 3, 4, 6, 9 to 11, and the irradiation amount was changed. except for changing from 500 mJ / cm ² to 4,000 mJ / cm ^2, as well as to produce a liquid crystal display device in the same manner as in example 1, like the electrical characteristics as in example 1, the evaluation of light resistance and the liquid crystal alignment property went. The results are shown in Table 1 below. Under the condition that the polymer (B-1) is irradiated with polarized ultraviolet rays containing a bright line of 313 nm at 500 mJ / cm ² , no photocleaving reaction occurs in the polymer (B-1). Therefore, the polymer (B-1) corresponds to a polymer that is not photosensitive with respect to the polyorganosiloxane (C).

[Example 9]
(1) Preparation of liquid crystal composition A compound represented by the following formula (L-1) and a compound represented by the following formula (L-2) as polymerizable monomers in a nematic liquid crystal (MLC-6221 manufactured by Merck). Liquid crystal composition LC1 is obtained by adding 0.5% by mass of the mixture (mass mixing ratio (L-1) :( L-2) = 50: 50) to the total amount of the monomeric liquid crystal and mixing. It was.

(2) Manufacture of a transverse electric field type liquid crystal display element A glass substrate having a metal electrode made of chrome patterned in a comb-tooth shape on one side and an opposing glass substrate having no electrode are paired to form an electrode of the glass substrate. Liquid crystal alignment agent E (the liquid crystal alignment agent used in Example 4) was applied to the holding surface and one surface of the opposing glass substrate using a spinner, prebaked on a hot plate at 80 ° C. for 1 minute, and then inside the oven. Was heated (post-baked) at 200 ° C. for 1 hour in an oven replaced with nitrogen to form a coating film having a thickness of 0.1 μm.
Next, each of the coating film surfaces is irradiated with polarized ultraviolet rays of 300 J / m ² containing a bright line of 313 nm from the substrate normal direction using an Hg-Xe lamp and a Gran Tailor prism (photoalignment treatment) to form a liquid crystal alignment film. A pair of substrates to have was obtained. An epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied to the outer periphery of the surface of one of the substrates having the liquid crystal alignment film by screen printing, and then the liquid crystal alignment film surfaces of the pair of substrates are opposed to each other. The substrates were overlapped and pressure-bonded so as to reverse the orientation when irradiated with polarized ultraviolet rays, and the adhesive was thermoset at 150 ° C. for 1 hour.
Next, the liquid crystal composition LC1 prepared in (1) above was filled in the gap between the substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Then, in order to remove the flow orientation at the time of liquid crystal injection, this is heated at 150 ° C. and then slowly cooled to room temperature, and further irradiated with UV light from the outside of the liquid crystal cell (irradiation amount: 2,000 mJ / cm ² (λ =). 365 nm)) was carried out without applying a voltage between the pair of electrodes. Next, a polarizing plate is attached to both outer surfaces of the substrate so that the polarization directions thereof are orthogonal to each other and the direction of projection of the polarized ultraviolet rays of the liquid crystal alignment film onto the substrate surface is orthogonal to the liquid crystal display. Manufactured the element.

(2) Evaluation The liquid crystal display element manufactured in (1) above was evaluated for its electrical characteristics, light resistance, and liquid crystal orientation in the same manner as in Example 1. As a result, in this example, VH ₁ = 99.2% and ΔVHR = 0.3%. In addition, the liquid crystal orientation was also good as in Example 1.

[Example 10 and Comparative Examples 12, 13]
The liquid crystal alignment agent used was changed as shown in Table 1 below, and for Comparative Example 13, the exposure wavelength during the photoalignment treatment was changed from 313 nm to 365 nm, and the irradiation amount was changed from 500 mJ / cm ² to 4,000 mJ / cm. ^A liquid crystal display element was manufactured in the same manner as in Example 9 except for the change to ² , and the electrical characteristics, light resistance, and liquid crystal orientation were evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[Example 11]
(1) Preparation of liquid crystal aligning agent 20 parts by mass of the polymer (A-2) obtained in Synthesis Example 2 as the polymer (A), and the polymer (B-) obtained in Synthesis Example 5 as the polymer (B). The amount of the solution containing 1) corresponding to 60 parts by mass in terms of the polymer (B-1) and the polymer (C-1) 20 obtained as the polyorganosiloxane (C) in Synthesis Example 4 above. Mix parts by mass, add N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) to this, and add 20 parts by weight of the compound represented by the following formula (E-1) as a polymerizable monomer to the solvent. A solution having a composition of NMP: BC = 50: 50 (mass ratio) and a solid content concentration of 4.0% by mass was prepared. The liquid crystal alignment agent T was prepared by filtering this solution through a filter having a pore size of 1 μm.

(2) Manufacture and evaluation of liquid crystal display element The point that the liquid crystal alignment agent used was the liquid crystal alignment agent T prepared in (1) above, and MLC-6221 (manufactured by Merck) was used between the substrates instead of the liquid crystal composition LC1. A liquid crystal display element was manufactured in the same manner as in Example 9 except that the gap was filled in the gap, and the electrical characteristics, light resistance, and liquid crystal orientation were evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

As is clear from Table 1, all of the liquid crystal display elements of Examples 1 to 11 had a high initial voltage holding ratio of 98.0% or more. In addition, ΔVHR was 0.9% or less in each case, and the light resistance was also good. Further, in Examples 1 to 11, the orientation of the liquid crystal was also good. On the other hand, the liquid crystal aligning agents of Comparative Examples 1 to 13 were inferior in at least one of the initial voltage retention rate and the light resistance as compared with those of Examples 1 to 11. Regarding the liquid crystal orientation, in Comparative Example 2, the orientation of the liquid crystal was not observed, and instead of the polymer (A), a (meth) acrylic polymer showing no liquid crystal property was used (Comparative Examples 5 to 9). Then, many orientation defects were observed when the voltage was applied / released. Further, in Comparative Example 10 in which the polymer (B-2) which is a photosensitive polyamic acid was used instead of the photosensitive polyorganosiloxane (polyorganosiloxane (C)), many orientation defects were observed.

Claims (7)

It contains a polyorganosiloxane (C) having a photo-oriented group and a polymer (A) containing a partial structure exhibiting liquid crystallinity and exhibiting liquid crystallinity .
The polymer (A) is a liquid crystal alignment agent which is a polymer of a monomer having a polymerizable unsaturated bond . The liquid crystal alignment agent according to claim 1, which contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester and polyimide. A liquid crystal alignment film formed by using the liquid crystal alignment agent according to claim 1 or 2 . A liquid crystal element comprising the liquid crystal alignment film according to claim 3 . A step of applying the liquid crystal alignment agent according to any one of claims 1 to 3 on a substrate to form a coating film, and irradiating a substrate surface coated with the liquid crystal alignment agent with light to apply a liquid crystal to the coating film. A method for producing a liquid crystal alignment film, which comprises a step of imparting orientation ability. A step of forming a liquid crystal alignment film on each surface of a pair of substrates by the method according to claim 5 ,
A step of constructing a liquid crystal cell by arranging the pair of substrates via a liquid crystal layer containing a polymerizable monomer so that the liquid crystal alignment films face each other.
A method for manufacturing a liquid crystal element, which comprises a step of irradiating the liquid crystal cell with light. A step of forming a liquid crystal alignment film on the surface of each of the pair of substrates using a liquid crystal alignment agent containing a polymerizable monomer by the method according to claim 5 .
A step of constructing a liquid crystal cell by arranging the pair of substrates via a liquid crystal layer so that the liquid crystal alignment films face each other.
A method for manufacturing a liquid crystal element, which comprises a step of irradiating the liquid crystal cell with light.